At present bobbin changing on ring spinning machines is usually a random operation, meaning that roving bobbins are exchanged and replaced by new full bobbins only when empty or substantially empty, the exact position of the emptying bobbins not being known in advance but being distributed statistically over the whole length of the ring spinning machine.
However, random changing leads to lost output since discovering that a particular roving bobbin is empty, removal of this empty bobbin and insertion of a full bobbin takes some time. There is also some downtime since the operators are often not in a position to immediately change all of the bobbins which are becoming empty. Another cause of lost output is that the roving of a new full bobbin must first be led through the drafting unit and then connected to the trailing or running-out end of the ring-spun yarn produced from the previous bobbin.
To obviate this loss of time an apparatus has already been suggested which enables the trailing end of the roving to be connected automatically to the entering or leading end of the new roving. The aforementioned known apparatus is disclosed in published European Patent Application No. 296,546, the disclosure of which is incorporated herein by reference. The design of that known apparatus makes it easier to employ bobbin exchanging in blocks, i.e., a so-called block change, in accordance with the present invention.